VulnerabilityAnalyzed
CVE-2026-55009
Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to elevate privileges locally.
HIGH 7.8EPSS 2.51%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (2.51%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to elevate privileges locally.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 2.51% probability · 84th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-502
- Affected
- microsoft/exchange server · microsoft/exchange server subscription edition
- Source
- secure@microsoft.com
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.